With the development of Information Technology (IT), the quantity of data transmitted has increased dramatically. Accordingly, businesses pay increased attention to the integrity and reliability of their own information.
While managing company, enterprise or customer networks that are provided by an Internet Service Provider (ISP), an IT administrator needs to communicate securely. Because confidential information of the enterprise can be involved, security is very important. In a conventional approach, a separate communication line needs to be provided, either through phone, or other personal communication devices, to meet the security requirement. However, it is not convenient, and is expensive.